title: Droplet manipulation by an external electric field for crystalline film growth.
abstract: Combining droplet manipulation by the application of an electric field with inkjet printing is proposed as a unique technique to control the surface wettability of substrates for solution-processed organic field-effect transistors (FETs). With the use of this technique, uniform thin films of 2,7-dioctyl[1]benzothieno[2,3,-b][1]benzothiopene (C8-BTBT) could be fabricated on the channels of FET substrates without self-assembled monolayer treatment. High-speed camera observation revealed that the crystals formed at the solid/liquid interface. The coverage of the crystals on the channels depended on the ac frequency of the external electric field applied during film formation, leading to a wide variation in the carrier transport of the films. The highest hole mobility of 0.03 cm(2) V(-1) s(-1) was obtained when the coverage was maximized with an ac frequency of 1 kHz.
authors.affiliation: Center for Organic Photonics and Electronics Research, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Komino
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kuwabara
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ikeda
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yahiro
authors.forename: Kazuo
authors.initials: K
authors.lastname: Takimiya
authors.forename: Chihaya
authors.initials: C
authors.lastname: Adachi